壳聚糖/聚己内酯接枝共聚物的均相合成与表征

Homogeneous synthesis and characterization of graft copolymer of chitosan/polycaprolactone

以离子液体1-丁基-3-甲基咪唑醋酸盐([BMIM]Ac)为反应介质,研究了壳聚糖与ε-己内酯的均相接枝共聚反应,考察了反应温度、时间、催化剂用量等对接枝率的影响,并利用红外光谱、核磁共振氢谱、热重分析、X射线衍射等对接枝共聚物进行了表征。结果表明,均相条件下壳聚糖与ε-己内酯的接枝共聚反应时间短、效率高,在反应温度为105℃,反应时间为8 h,催化剂Sn(OCt)2的用量为ε-己内酯质量的0.1%,ε-己内酯与壳聚糖摩尔比为20时,接枝率达到了近250%;ε-己内酯的接枝引入改变了原始壳聚糖的结晶结构,导致接枝共聚物的热稳定性较原始壳聚糖有所降低。

The homogeneous graft copolymerization of ε-caprolactone（ε-CL）onto chitosan（CS）in ionic liquid 1-butyl-3-methylimidazolium acetate（Ac）was studied.The effect of various reaction parameters on grafting percentage was evaluated and the obtained graft copolymer was characterized by FTIR,1H NMR,TGA and XRD.The results showed that graft copolymerization occurred with high reaction efficiency under the homogeneous conditions,and the grafting percentage of 250% was achieved at temperature 105℃,time 8 h,catalyst concentration 0.1%（mass） of ε-CL and molar ratio ε-CL to CS 20.The thermal stability of graft copolymer decreased as compared with CS,because of a variety of crystal structures of CS occurring with the grafting of ε-CL onto CS.